Characterizations of Rice Bran Nanofibers Produced by Enzymatic Treatment and Their Role in Stabilizing Oil-in-Water Pickering Emulsions

Purpose In this work, rice bran nanofibers (RBN) were produced from defatted rice bran (DRB) using an enzymatic method, as an alternative to replace the harsh chemical usage in the traditional preparation of nanocellulose. The effect of using two different enzymes; cellulase (hydrolytic enzyme) and laccase (ligninolytic enzyme) on the physicochemical and emulsifying properties of the RBN produced, were investigated.MethodFollowing the alkaline and ultrasonic pretreatment, an enzymatic treatment using two types of enzymes (cellulase and laccase) was carried out to produce RBN. Characterization studies were conducted on the produced RBN which was then used to stabilize oil-in-water Pickering emulsions.ResultsCharacterization studies conducted on the RBN proved that it was best prepared by using laccase enzyme compared to cellulase resulting in nanofibres with a diameter of 8.691 nm, 49.91% crystallinity and zeta potential of - 32.50 mV. This is due to the delignification function of the laccase enzyme that caused around 29.6% lignin reduction which facilitates the exploitation of the cellulose content of RBN. A stable oil-in-water Pickering emulsion was also observed within 30 days of storage when laccase-treated RBN were used.ConclusionResults obtained indicate that the laccase-treated RBN exhibited promising characteristics with the robust emul-sifying ability for the fabrication of novel industrial Pickering emulsions for food, cosmetics and pharmaceutical industries [GRAPHICS]